Marshalling Cabinet or Marshalling Panel

As discussed in the Typical Architecture of Instrumentation and Automation System, the automation architecture of the plant is having a

marshalling cabinet in between the junction box and the system cabinet. This marshalling cabinet function is to interface the incoming field

cable (which is normally a multipair cable) and the I/O (Input/Output) card connection. Without marshalling cabinet, we can sure (for large

number of I/O) that there will be a trouble for operation personnel to maintain and operate the cabling.

One of the important interface function of the marshalling cabinet is the cross wiring function. Cross wiring is always necessary since the

incoming field signal and the channel quantity of the I/O card is always different. For example let’s say we have a 24 pair incoming field cable

that carry 20 field analogue signal. This field signal will be split at least into two analogues 16 channel I/O card. The First 16 I/O will be in the

first 16 channel I/O card and the other 4 will be in the next 16 channel I/O card. To have this split wiring (cross wiring) in the system cabinet is

not a good practice from the operation and maintenance point of view. Thus the marshalling cabinet is needed.

Another cause of the cross wiring is the mixed of I/O signals that coming from the field. The incoming multipair cable can have mixed AI

(Analaogue Input) and AO (Analogue Output) signal in the same multipair cable. This mixed signal will be split in the marshalling cabinet so that

the AI signal will be terminated in the dedicated AI termination board and so do the AO signal.

In some application such as voting application for safety system (i.e. 2oo3 voting) there is a requirement to have the I/O signal allocated in the

different I/O card so that the common fault cause can be avoided. This application ofcourse once again need a cross wiring in the marshalling

cabinet.

In typical application, the marshalling cabinet is having the following cable routing.

1.       The multipair field cables enter the marshalling cabinet through the bottom part of the cabinet.

2.       Then each wire of the incoming multipair field cable is terminated in the surge protection devices or surge arrester. If there is no requirement

of such surge protection devices, each wire is terminated in the terminal block.

3.       From the surge protection devices, in Non IS application, there will be a cross wiring that match the field signal and the I/O address assignment

in the termination board. If the system is IS, then before cross wiring, each wire connection is routed first to the IS Barrier.

4.       The dedicated system cable that has a ‘plug and play’ connection is then routed from the termination board to the I/O card in the system

cabinet.

5.       Some termination board may require a dedicated DC power supply that can be taken from the DC power supply in the marshalling cabinet.

Typical Architecture of Instrumentation & Automation System

In general application, the instrumentation and automation architecture is consist of field instruments, individual & multicore cable, junction

boxes, marshalling cabinet, and system cabinet. Each of them is combined together so that the control loop application can be performed

correctly.

The field instruments are any of the instrument equipment used to measure and control the process variables. Such type of instruments is

pressure transmitter, temperature transmitter, flow transmitter, level transmitter, control valves, solenoid valves etc. This device is act as a

front liner in the instrumentation control loop.

The cables, both individual and multicore, are used to connect the field instruments with the controller. This cables is used as a signal or power

transmission. First of all, the individual field instruments are connected by and individual cables to a junction box. This junction box is used to

re-connect the individual cables with the respective multicore cables. So, instead of laid up the individual cables for each instruments to the

control room, we laid up the multicore cables (usually comes in big size) to the control room.

The marshalling cabinet is used as a place to do a cross wiring of the multicore cables with the respective terminal block allocations. The

arrangements of the multicore cables that come from field usually didn’t come in the control loop point of view. And usually, the ICS vendors

have their own arrangement regarding their I/O module and the respective controller. So they do a cross wiring in this marshalling and the

incoming multicore cables adapt the arrangement of the I/O and controller make by ICS vendors.

The system cabinet is used to place all the I/O card/module and also the controller it self. All the wire that has already arranged in the

marshalling goes to this cabinet directly without any more difficult arrangement. The incoming cables comes to this cabinet has already tidy and

match with their respective I/O channels. In this controller, the signal comes in and comes out from and to the field to establish a complete

control loops. Below is the typical instrumentation architecture illustration that widely used in the any oil & gas projects.

Typical Inspection and Test Requirement of Control Valvesby 

admin

1   Comment  

Visual Test as per MSS SP-55 Dimensional Test:

Face-to-face dimensions as per ANSI/ISA-75.08.01, ANSI/ISA-75.08.06, and ASME B16.10.

Flange facings and dimensions as per ASME B 16.5

Check of Body Marking as per ASME B 16.5, ASME B 16.34, and MSS-SP 25. Chemical analysis and mechanical properties as per the applicable ASTM material code Nondestructive test as per ASME B 16.34 Hydrostatic test as per ASME B 16.34 or MSS-SP61 Seat leakage test as per ANSI/FCI 70-2. Actuator Leakage Test at 1.5 times maximum design pressure. Functional and Performance test (i.e. hysteresis plus deadband, linearity, repeatability, etc) as per IEC

60534-4 and ISA 75.13.01 For electrical accessories (such as solenoid valve, I/P positioner, position transmitter etc):

Functional Test Electrical type and routine test as per IEC 61010-1

Applicable Standards and Codes:

MSS SP-55 ~ Quality Standards for Steel Castings for Valves, Flanges, Fittings and Other Piping Components – Visual Method for Evaluation of Surface Irregularities

IEC 60534-3-1 ~ Industrial-Process Control Valves – Part 3-1: Dimensions – Face-to-Face Dimensions for Flanged, Two-Way, Globe-Type, Straight Pattern and Centre-to-Face Dimensions for Flanged, Two-Way, Globe-Type, Angle Pattern Control Valves

ASME B 16.10 ~ Face-to-Face and End-to-End Dimensions of Valves

ASME B 16.5 ~ Pipe flanges and flanged fittings NPS 1/2 through NPS 24 metric/inch standard

ASME B 16.34 ~ Valves – Flanged, threaded and welding ends

MSS-SP61 ~ Pressure Testing of Valves

ANSI/FCI 70-2 ~ Control Valve Seat Leakage

MSS-SP 25 ~ Standard Marking System for Valves, Fittings, Flanges, and Unions

IEC 60534-4 ~ Industrial-Process Control Valves – Part 4: Inspection and Routine Testing

ISA 75.13.01 ~ Method of Evaluating the Performance of Positioners With Analog Input Signals and Pneumatic Output

IEC 61010-1 ~ Safety requirements for electrical equipment for measurement, control, and laboratory use – Part 1: General requirements

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Temperature Transmitter Calibrationby 

admin

Published on 12-15-2011 02:58 AM

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Typical Procedure:

1. Set up the temperature transmitter as shown in the picture below.2. Switch on the thermo bath / temperature generator power supply.3. Check the temperature transmitter span in the related datasheet.4. Carry out the five point calibration start from 0% to 100% of span range value.5. First, set the temperature at temperature bath to 0% of the transmitter span range value.6. Read the ampere meter reading (wait until the reading is stable) and record it.7. Repeat step 5 to 6 for 25%, 50%, 75%, and 100% of the transmitter span range value.8. Repeat step 5 to 6 for downscale start from 100%, 75%, 50%, 25%, and 0%.9. Calculate the % error for each test point and check whether it still under an acceptable range.10. If all result still in the acceptable % error range, then the calibration is finish. If there is some test point

that shows the result out of acceptable % error range, then do the next step.11. Set temperature bath at 0% of the transmitter span range value. The ampere meter reading shall be 4

mA. If the reading is already 4 mA then continue to next step. If the reading not 4 mA then adjust the zero potentiometer of transmitter until the ampere meter read 4 mA. The zero adjustment also available though HART communicator by using zeroing application.

12. Set temperature bath at 100% of the transmitter span range value. The ampere meter reading shall be 20 mA. If the reading is already 20 mA then back to step 5. If the reading not 20 mA then adjust the span potentiometer of transmitter until the ampere meter read 4 mA. The span adjustment also available though HART communicator by using span application.

Below is example of temperature transmitter calibration with span 100 oC with minimum temperature

range is 35 oC. This calibration is concluded as satisfactory since all test point are have the % Error of Span under the rated % Error of Span stated in the datasheet (lets say 0.25% of span).

Test Point

Ampere Meter Reading (mA)

Thermo Bath Temperature

Span of Transmitter

Error Calculation % Error of Span

0% 4.01 35 oC 100 oC (((((4.01-4)*100/16))+35)-35)/100*100

0.0625

25% 7.97 60 100 oC (((((7.97-4)*100/16))+35)-60)/100*100

-0.1875

50% 11.99 85 100 oC (((((11.99-4)*100/16))+35)-85)/100*100

-0.0625

75% 16.02 110 100 oC (((((16.02-4)*100/16))+35)-110)/100*100

0.125

100% 20.03 135 100 oC (((((20.03-4)*100/16))+35)-135)/100*100

0.1875

75% 15.99 110 100 oC (((((15.99-4)*100/16))+35)-110)/100*100

-0.0625

50% 12.01 85 100 oC (((((12.01-4)*100/16))+35)-85)/100*100

0.0625

25% 8.03 60 100 oC (((((8.03-4)*100/16))+35)-

0.1875

60)/100*100

0% 3.97 35 oC 100 oC (((((3.97-4)*100/16))+35)-35)/100*100

-0.1875

Notes:To calculate the % Error of Span we can apply the following equation derived from simple linear interpolation.% Error of Span = (((((I-4)*Span/16)) +Io)-TB)/Span *100Where I = Ampere Meter ReadingIo = 0% Span TemperatureTB = Thermo Bath Temperature

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Pressure Transmitter Calibrationby 

admin

Published on 12-15-2011 02:21 AM

2   Comments  

Typical Procedure:

1. Set up the pressure transmitter as shown in the picture below.2. Check the pressure transmitter span in the related datasheet.3. Carry out the five point calibration start from 0% to 100% of span range value.4. First, set the pressure of a dead weight tester or hydraulic pump at pressure equal to 0% of the transmitter span range value.5. Read the ampere meter reading (wait until the reading is stable) and record it.6. Repeat step 5 to 6 for 25%, 50%, 75%, and 100% of the transmitter span range value.7. Repeat step 5 to 6 for downscale start from 100%, 75%, 50%, 25%, and 0%.8. Calculate the % error for each test point and check whether it still under an acceptable range.9. If all result still in the acceptable % error range, then the calibration is finish. If there is some test point that shows the result out of acceptable % error range, then do the next step.10. Set dead weight tester pressure at 0% of the transmitter span range value. The ampere meter reading shall be 4 mA. If the reading is already 4 mA then continue to next step. If the reading not 4 mA then adjust the zero potentiometer of transmitter until the ampere meter read 4 mA. The zero adjustment also available though HART communicator by using zeroing application.11. Set dead weight tester pressure at 100% of the transmitter span range value. The ampere meter reading shall be 20 mA. If the reading is already 20 mA then back to step 5. If the reading not 20 mA then adjust the span potentiometer of transmitter until the ampere meter read 4 mA. The span adjustment also available though HART communicator by using span application.See Temperature Transmitter Calibration for example of calibration tabulation & % Error calculation.

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Typical Calibration Procedure of Temperature Transmitterby 

admin

Published on 12-15-2011 02:15 AM

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1. Set up the temperature transmitter, HART communicator, power supply, RTD/TC simulator, and the multimeter as below (see below calibration setup file).

2. Apply a temperature to the transmitter (through RTD/TC simulator) equal to a lower range temperature (usually it correspond to 4 mA in the transmitter output). For example we have 0 to 100 Celcius calibrated range, then the lower range temperature is 0, or let’s say we have -5 C to 100 C then we have lower range pressure equal to -5 C.

3. Read the temperature in the transmitter LCD (or in the HART communicator). Adjust (if any) through the HART communicator so that the output of the transmitter (on LCD) is the same with the applied temperature.

4. Read the mA output of the transmitter by using a multimeter. Adjust (if any) through the HART communicator so that the output of the transmitter (on multimeter) is 4 mA.

5. Apply a temperature to the transmitter equal to an upper range temperature (usually it correspond to 20 mA in the transmitter output).

6. Read the temperature in the transmitter LCD (or in the HART communicator). Adjust (if any) through the HART communicator so that the output of the transmitter (on LCD) is the same with the applied temperature.

7. Read the mA output of the transmitter by using a multimeter. Adjust (if any) through the HART communicator so that the output of the transmitter (on multimeter) is 20 mA.

Typical tools required:

1. 24 VDC power supply2. Multimeter digital3. RTD/TC simulator.4. HART communicator5. Screwdriver toolkit

Note: point number 1, 2, 3, and 4 of the typical tools above can be replaced by a single multitester available in the market.This typical maintenance procedure is just an illustration of how to regularly service a temperature transmitter for academic purpose only. This typical procedure shall not be used as day to day operation guidance. The vendor specific maintenance manual shall be used in detail.

Read more: http://www.instreng.com/content/121-typical-calibration-procedure-temperature-transmitter.html#ixzz2p24gNsFl

Typical Calibration Procedure of Magnetostrictive Level Transmitterby 

admin

Published on 12-15-2011 02:45 AM

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Before we calibrate the magnetostrictive level transmitter, we must aware that the float has been produced at factory as per process fluid Specific Gravity (SG), while we will use water as the calibration fluid. When the magnetostrictive is operated by using actual process fluid, let say it will show the fluid level on 50% float immersion. If we use other fluid (typically water for calibration purpose) the float immersion might be less than 50% or more than 50%, depends on the float designation. Thus by using water as calibration fluid, there will be some 'offset'.

The offset problem as explained above can be solved if the magnetostrictive level transmitter is mounted on the magnetic level gauge that has an analogue level indicator. By using the analogue level indicator, we just need to fill the water until the shuttle or flag indicator in the magnetic level gauge reach the 0% or 100% level without further inspection whether the float and liquid level reach the same level. This is possible because the magnetostrictive level transmitter is detecting the position of the magnet it self rather than the float immersion on the fluid. If the magnetostrictive doesn't have any local analogue indicator (magnetic shuttle or flag), we need to disassembly the level transmitter and manually move the float to 0% and 100% level position.

Therefore there are two types of calibration methods, one is using local gauge (magnetostrictive is mounted on magnetic level gauge) and the other one is manually moving the float (direct insertion type). The water will be used as calibration fluid due to difficulty to use the actual process fluid as calibration fluid.

Magnetostrictive Level Transmitter Mounted on Magnetic Level Gauge

1. Set up the magnetostrictive level transmitter, HART communicator, power supply, and the multimeter as below (see below calibration setup file). Attach it to column or temporary support.

2. Check the configuration of the lower range value (0% level, 4 mA) and high range value (100% level, 20 mA). Make sure that the inputted data is as per datasheet. For example, the lower range value is 10 inch and the high range value is 35 inch (both of it are measured from the bottom of level transmitter probe)

3. Fill the level transmitter chamber with water up to the 0% level (as indicated by magnetic shuttle or magnetic flag). Read the level measurement in the transmitter LCD (or in the HART communicator). Set this condition as 0% level through HART communicator.

4. Read the mA output of the transmitter by using a multimeter. Adjust (if any) through the HART communicator so that the output of the transmitter (on multimeter) is 4 mA.

5. Fill the level transmitter chamber with water up to the 100% level (as indicated by magnetic shuttle or magnetic flag). Read the level measurement in the transmitter LCD (or in the HART communicator). Set this condition as 100% level through HART communicator.

6. Read the mA output of the transmitter by using a multimeter. Adjust (if any) through the HART communicator so that the output of the transmitter (on multimeter) is 20 mA.

Magnetostrictive Level Transmitter Direct Mount Type

1. Set up the magnetostrictive level transmitter, HART communicator, power supply, and the multimeter as below (see below calibration setup file). Attach it to column or temporary support.

2. Check the configuration of the lower range value (0% level, 4 mA) and high range value (100% level, 20 mA). Make sure that the inputted data is as per datasheet. For example, the lower range value is 10 inch and the high range value is 35 inch (both of it are measured from the bottom of level transmitter probe)

3. Manually move the float to the 0% level. Read the level measurement in the transmitter LCD (or in the HART communicator). Set this condition as 0% level through HART communicator.

4. Read the mA output of the transmitter by using a multimeter. Adjust (if any) through the HART communicator so that the output of the transmitter (on multimeter) is 4 mA.

5. Manually move the float to the 100% level. Read the level measurement in the transmitter LCD (or in the HART communicator). Set this condition as 100% level through HART communicator.

6. Read the mA output of the transmitter by using a multimeter. Adjust (if any) through the HART communicator so that the output of the transmitter (on multimeter) is 20 mA.

Alternate Calibration Procedure for Direct Mount Type (on chamber only without local indicator)

1. Get float projection calculation from the Vendor. Get this float projection for two values, one for operating specific gravity and one for water as calibration fluid. This float projection calculation will tell to us how deep the float will be immersed in the operating fluid and in the water.

2. Calculate the equivalence of water level (for lower range value and high range value) to the operating fluid level by using that float projection data. If the float immersion level by using water as calibration fluid is less than the immersion level by using the operating fluid, then subtract the 0% lower range value and 100% high range value by the difference between that two float projection. If the float immersion level by using water as calibration fluid is more than the immersion level by using the operating fluid, then add the 0% lower range value and 100% high range value by the difference between that two float projection. Example, float projection of the operating fluid is 5", by using water is �4.5". The lower range value set in the transmitter is 6" from the bottom of probe. Then water level that � �we must apply to the level transmitter chamber shall equal to 6 inch - (5 inch -4.5 inch) = 5.5 inch. When the water level reaches this 5.5 inch, the transmitter should show 0% level.

3. Set up the magnetostrictive level transmitter, HART communicator, power supply, and the multimeter as below (see below calibration setup file). Attach it to column or temporary support.

4. Check the configuration of the lower range value (0% level, 4 mA) and high range value (100% level, 20 mA). Make sure that the inputted data is as per datasheet. For example, the lower range value is 10 inch and the high range value is 35 inch (both of it are measured from the bottom of level transmitter probe)

5. Fill the level transmitter chamber with water up to the equivalence 0% level (as calculated above). Read the level measurement in the transmitter LCD (or in the HART communicator). Set this condition as 0% level through HART communicator.

6. Read the mA output of the transmitter by using a multimeter. Adjust (if any) through the HART communicator so that the output of the transmitter (on multimeter) is 4 mA.

7. Fill the level transmitter chamber with water up to the equivalence 100% level (as calculated above). Read the level measurement in the transmitter LCD (or in the HART communicator). Set this condition as 100% level through HART communicator.

8. Read the mA output of the transmitter by using a multimeter. Adjust (if any) through the HART communicator so that the output of the transmitter (on multimeter) is 20 mA.

Typical tools required:

1. 24 VDC power supply2. Multimeter digital3. Water Supply Connection4. HART communicator5. Screwdriver set6. Wrench set

Note: point number 1, 2, and 4 of the typical tools above can be replaced by a single multitester available in the market.

This typical maintenance procedure is just an illustration of how to regularly service a magnetostrictive level transmitter for academic purpose only. This typical procedure shall not be used as day to day operation guidance. The vendor specific maintenance manual shall be used in detail.

Read more: http://www.instreng.com/content/125-typical-calibration-procedure-magnetostrictive-level-transmitter.html#ixzz2p24mf5hJ

Control Valve Trim Typeby 

instreng

Published on 01-10-2013 07:53 AM

0   Comments  

As per ISA S-7505 trim is defined as the internal parts of a valve which are in flowing contact with the controlled fluid. Usually it contains a plug, seat, & stem. The body & bonnet of a valve isn’t considered as part of the trim. Valve trim could be in the several types. The classification by valve manufacturer can be as per seat material used, trim function, and guided used.

As per seat material used:1. Soft seated trim valve.Soft seated valve is a Globe valve trim with an elastomeric, plastic or other readily deformable material used either in the valve plug or seat ring to provide tight shutoff with minimal actuator forces. (ISA S-7505)Soft seated trim use non metallic material such as PTFE, Graphite etc. We can use soft seated trim if the valve will not service a flashing, cavitating, or other slurry services.2. Metal seated trim material.Metal seated trim valve is a valve which uses a metal as a seat material such as 316 SS, Monel, etc. Best used for the severe service, flashing, cavitating, and slurry services.

As per trim function:1. Standard trim.Globe valve trim that designed for general service fluid without flashing, cavitating, or other slurry services. Usually comes in form of contoured plug.2. Anti cavitation trim.Globe valve trim that designed for fluid that have cavitation behavior. This special designed trim usually comes in form of cage guided or multistage plug.3. Anti noise trim.Globe valve trim that designed for fluid that have high noise radiated because of high power of fluid flow. Usually this trim design comes in form of multistage, cage guided or labyrinth type.

As per guide type:Post guidedIn the post guided trim type, the plug is guided by a bushing in the stem or part of the plug. This post guided valve usually used in the general service fluid that doesn’t exhibit cavitation, flashing, or high noise behavior.Cage guidedIn the cage guided trim type, the plug is guided by a cage surrounding the plug. This cage guided valve usually used in the fluid service that have cavitation, high noise or flashing effect.Generally, the trim material of a valve shall refer to any specific project piping class or control valve specification required by client. In the data sheet, we could specify the trim type as metal seated-standard trim-post guided, metal seated-anti cavitation-cage guided trim etc.

http://www.instreng.com/content/attachments/71d1357804413-low-noise-trim.jpg.html

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Emergency Shutdown (ESD) System Philosophyby 

info

Published on 01-06-2013 11:43 AM

2   Comments  

There are several purposes of the ESD System which is:

Protection of personnel Protection of the environment Minimize loss of production and damage to plant assets

Typically, the ESD System could fulfill the above objective by the following implementation:

Monitoring of an operational or equipment condition Automatic action in case of process hazardous conditions is exist by de-energizing

electrical equipment, shutting down and/or isolating process equipment and, isolating and depressurizing the installation.

Enabling manual initiation of ESD actions through ESD push button all around the plant. Monitoring the Fire & Gas conditions (F&G) by the F&G System Automatic action in case of F&G hazardous conditions exist by providing audible and visual

alarms for personnel.

Typical ESD System Component

Dedicated process transmitters Logic Solver Shut-Down valves (SDV), Fail to Close type, the purpose of this valve is to isolate. Blowdown valves (BDV), Fail to Open type. The purpose of this valve is to depressurize.

In practice the plant is usually divided into several isolable units that can be depressurized and isolated.

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This article was originally published in forum thread: Emergency Shutdown (ESD) System Philosophy started by info View original post

1. Categories: 

2. Automation System

 2 Comments

1.

Mark_Wallace13 - 03-14-2013, 08:43 AM

o   Reply

The last item of the typical Implementation of the ESD: "• Automatic action in case of F&G hazardous conditions exist by providing audible and visual alarms for personnel."

I think that is incorrect, the Fire & Gas is the Detection and Alarming System to activate Audible and visual alarms, the ESD will as per line above montior the F&G conditions.The ESD will trip on alarms from the F&G and other independant systems - High Integrity Pressure Protection Systems (HIPPS), Process Shutdown (PSD), Burner Management System (BMS), Unit Contol Panels (UCPs), Heat, Ventilation and Air Conditioniting (HVAC), Deluge and Firewater Pumps etc. The ESD may trip the F&G System and/or Public Alarm/General Annoucement /PAGA) Systems or maybe activate some warnings but never the F&G Alarms direct.

1.

battww - 09-10-2013, 09:36 AM

o   Reply

The highest level of protection is Emergency Shutdown (ESD). At this level, all process systems are shut down. All incoming/outgoing lines are isolated, and, quite often, all support equipment is shut down. These shutdowns usually result from the detection of catastrophic conditions such as fire and major gas or oil leaks, or operator decision. Also, in the case of fire, it might be desirous to automatically start fire pumps, activate deluge systems, etc. Each shutdown level is interlocked with the next lower level. That is, ESD will initiate process system shutdown, process system shutdown will initiate process train shutdown, and so on. The lowest level of the system, alarm only, stands alone.

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NEC Cable SelectionRate this Entry0 Comments

by 

Beatriz

, 12-28-2013 at 07:58 AM (21 Views)

A document to explained the cable selection in NEC standard.

Cable selection in NEC project (for IEC practiced engineers)When you select a LV cable in a project which uses NEC as the wiring code, the following must be observed.

I referred NEC 2008 and IEE 1992.1. 125% rule ( or may be 80% rule)Your cable must have 125% current carrying capacity against continuous load. This is not a 25% design margin nor for future load, simply you can not use this 25% forever.

In NEC and UL, MCCB, MCC and panel board rating is three hours rating, but not continuous. For continuous load, or load which is continuous for more than 3 hours, MCCB rating must be greater than 1.25 times the load current. For instance, continuous load of 100A requires 125AT MCCB at least. If you select 100A MCCB for 100A load, it may trip if the current of 100A continues more than three hours. The power cable connecting this load is protected by this 125A MCCB, thus the current carrying capacity of the cable is 125A minimum, which means you need a 125A cable for 100A load.

Cable current carrying capacity >= MCCB rating >= 1.25 times continuous load current

Refer to NEC 210.19(A)(1), 210.20(A), 240.4

IEE NoteCable current carrying capacity >= MCCB rating >= Continuous load current

Refer to IEE 433-02-01 (1) and (2)

2. Many ACBs and some MCCBs are 100% continuous rating.

If your ACB or MCCB together with the enclosure is 100% continuous rating, the item 1, above 125% rule does not apply. Such equipment or device has normally large rating current such as 500A or larger.

Cable current carrying capacity >= MCCB rating >= Load current

However, as far as I know, most of LV loads are fed from 3 hours rating panels. Practically, 100% continuous rating is only for ACB.

Refer to NEC 210.19(A)(1) Exception No.1, 210.20(A) Exception

3. For cable protection, the next higher standard over-current device permitted.

NEC permits a cable is protected with next higher OC device. for instance cable with 100A current carrying capacity must be protected by 100A MCCB, however, 101A current carrying capacity cable can be protected by 110A MCCB which is next higher standard of 101A.

The rule shown in item 1 above needs to change to this way.

Cable current carrying capacity >= 1.25 times continuous load currentAndMCCB rating >= 1.25 times continuous load current.AndCable current carrying capacity >= next higher MCCB rating

Refer to NEC 210.19 (A)(1), 210.20(A), 240.4 (B)For standard ampere rating, refer to NEC 240.6(A).

4. Conductor temperature in a panel board is 60 or 75 deg C.Your XLPE cable has maximum conductor temperature of 90 deg.C. However, you must keep the conductor temperature in the panel 60 or 75 deg C depending on the panel. If you can specify the conductor temperature of a panel, specify 75 deg C. There is no LV panel with 90 deg C available. In a panel, there is no need to apply group factor to reduce current carrying capacity.Current carrying capacity of a cable =Current carrying capacity of the cable at 60 or 75 deg. C without applying a group factorOrCurrent carrying capacity of the cable at 90 deg. C with applying a group factor.whatever smaller one.

Refer to NEC 110.14(C)(1)Refer to IEE 512-02-01

5. 2.5 mm2 16A, 4 mm2 20A, 6mm2 32ANEC requires small cables must be protected by the following OC protection.

14AWG (= 2.08mm2): 15A12AWG (=3.31mm2): 20A10AWG (=5.261mm2): 30A

IEC interpretation.2.5mm2: 16A4mm2: 20A6mm2: 30A

You must apply 80% rule here.

Refer to NEC 240.4(D)(3), (5) and (7)

6. All power and control cables must include PE.

Even though you can purchase IEC standard cables without PE, you should not do it. An NEC oriented client will never accept the explanation of IEC or interpretation of NEC with PE-less cables.

Another important thing you should never forget is all HV, MV, LV power and control cable must have PE within each cable. Single core cables are the only exception to this rule. PE is called as EGC (Equipment Grounding Conductor) in NEC and the function is exactly same as PE. EGC insulation color is either green or green/yellow. Un-insulated EGC in a cable is also acceptable. Metal cable amour can be treated as EGC.

Refer to NEC 250.134(B) and 300.3(B)

Read more: http://www.instreng.com/blogs/beatriz/38-nec-cable-selection.html#ixzz2p25THHPV

nspection & Test Plan for Shutdown Valves (including Actuator and Local Panel)Rate this Entry0 Comments

by 

isalib

, Yesterday at 02:08 PM (4 Views)

 Originally Posted by isalib 

No. Activity Description Reference Doc. COMP CTR VDR

BALL VALVES

1 Check of Material Certificates for Body, Ball, Seat, Stem, and Bolts & Nuts.

Chemical Analysis

Mechanical Properties

Impact Test (if any as per related ASTM standard)

Other test (if any as per related ASTM standard)

Applicable ASTM standard for example, ASTM A350, ASTM A182 etc.

R R O

2 Non Destructive Test (NDT):

100% RT on cast body

100% Ultrasonic Test (UT) or 100% Magnetic Particle Inspection (MPI) on pressure containing parts

100% Dye Penetrant Test (DPT) on ball and seat ring

Positive Material Identification (PMI)

Applicable Project Specification

R R O

3 Visual & Dimensional Check

General Arrangement Drawing

R W O

4 Hydrotest:Shell testing @ 1.5 design pressureSeat testing @ 1.1 design pressure

Applicable Project SpecificationAPI 6DISO 5208

W W O

5 Fire Test Applicable Project SpecificationAPI 6FA / API 607

R R O

6 Torque Test Vendor torque test procedure

W W O

7 Marking Check MSS SP-25 / API 6D R W O

8 Check of Painting:Dry Film Thickness CheckColor checkVisual Inspection

Applicable Project Specification

R W O

9 Partial Stroke Test (If any)

Applicable Project SpecificationVendor Procedure

W W O

10 Check of Packing Applicable Project SpecificationVendor Procedure

R W O

ACTUATOR

11 Functional Test:Closing & Opening Time (including fail position)Partial Stroke Test (If any)Torque Test (on 0, 45, 90 degree opening)

Applicable Project SpecificationVendor Procedure

W W O

12 Pneumatic Pressure Test and Seal Test

Applicable Project SpecificationVendor Procedure

W W O

13 Visual and dimensional check

Applicable Project Specification

R W O

14 Check of Painting:Dry Film Thickness CheckColor check

Applicable Project Specification

R W O

Visual Inspection

LOCAL PANEL

15 Check of the degree protection certificate and hazardous area certificates.

Applicable Project Specification

R R O

16 Visual and dimensional check

Applicable Project Specification

R W O

17 Check of Painting:Dry Film Thickness CheckColor checkVisual Inspection

Applicable Project Specification

R W O

18 Check nameplates of panels and identification instruments labels

Applicable Project Specification

R W O

19 Check correctness assembling and layout of components, instruments and accessories

Applicable Project Specification

R W O

20 Verification easy accessibility, removal and interchangeability of the components

Applicable Project Specification

R W O

21 Check for leakages of pneumatic instruments

Applicable Project Specification

R W O

22 Hydraulic test for the air storage tank

Applicable Project Specification

R W O

Notes:The above inspection & testing plan (ITP) is just a typical ITP.R = ReviewW = WitnessO = OriginatorCOMP = COMPANYCTR = CONTRACTORVDR = VENDOR

Read more: http://www.instreng.com/blogs/isalib/40-inspection-test-plan-shutdown-valves-including-actuator-local-panel.html#ixzz2p25onh2q